1. Field of the Invention
The present invention relates to digital data transmission, and more articularly, to both an apparatus and a method for transmitting information from a digital versatile disc (DVD) via a network to a device which can display a user interface to control the display DVD information.
2. Description of the Related Art
In general, digital versatile disc (DVD) players decode a bit stream read from a disc using a video decoder installed therein, and convert the decoded video signal to an analog television (TV) signal using a scheme such as the National Television System Committee (NTSC) standard.
The structure of such a general DVD player is shown in FIG. 1. In FIG. 1, a spindle motor (SP) 104 rotates a disc 102. A pick-up unit 106 receives light which has been irradiated onto and reflected off the disc 102 to read data from the disc 102. Also, the pick-up unit 106 includes a deck mechanism capable of transporting the pick-up and loading the disc 102.
A radio-frequency amplifier (RF-AMP) 108 amplifies an RF signal picked up by the pick-up unit 106, removes noise, performs analog-to-digital conversion and detects a synchronization (sync) signal. A servo controller 110 controls the rotation of the disc 102 and the focusing and tracking of the pick-up in order to accurately read data from the disc 102, under the control of a system controller 116. An eight-to-fourteen modulation (EFM) signal output from the RF-AMP 108 is provided to a digital signal processor (DSP) 112.
The DSP 112 demodulates the EFM signal read from the disc 102 and performs phase compensation of data using a phase locked loop (PLL) based on the detected sync, descrambling, error detection/correction, and controlling of a buffer 114. The transmission rate of a signal written ,to the disc 102 is greater than or equal to that of a signal read through the DSP 112, so that the data processed in the DSP 112 is temporarily stored in the buffer 114 and then transmitted when an MPEG video decoder 128 and an MPEG audio decoder 130 require the data. The series of processes are carried out under the control of the |system controller 116 such that overflow or underflow does not occur in the buffer 114. Also, the DSP 112 detects the control data portion of the bit stream read from the disc 102, and provides the detected data to the system controller 116.
The data from the DSP 112 may be scrambled in order to prevent digital copying. In this case, the scrambled data is descrambled by a content scramble system (CSS) decoder 122. The descrambled data stream is a program stream described by the Moving Picture Expert Group (MPEG) standard. The program stream comprises a video pack having an MPEG-1 or MPEG-2 format, an audio pack having an MPEG, Audio Coding (AC)-3 or linear Pulse Coded Modulation (PCM) format, a sub-picture pack and a navigation pack.
The CSS decoder 122 descrambles the bit stream provided from the DSP 112, a demultiplexer (DEMUX) 124 demultiplexes the descrambled stream into the audio pack, the video pack, the sub-picture pack and the navigation pack, the MPEG video decoder 128 decodes the demultiplexed video pack, the MPEG audio decoder 130 decodes the demultiplexed audio pack, and a sub-picture decoder 132 decodes the demultiplexed sub-picture pack such as a menu or caption. A video mixer 134 mixes the decoded video data and the sub-picture data, and a video digital-to-analog converter (DAC) 136 converts the output of the video mixer 134 to an analog signal. Then, the analog encoded video signal is output through a video encoder 138. An audio DAC 140 outputs the audio data decoded by the MPEG audio decoder 130 as an analog audio signal.
A central processing unit (CPU) interface (I/F) 126 interfaces with the system controller 116 such that the MPEG video decoder 128, the MPEG audio decoder 130 and the sub-picture decoder 132 perform decoding at a given timing according to the MPEG format.
A first memory 118 for storing various programs required by the system controller 116, may be comprised of an Erasable Programmable Read-only Memory (EPROM), and a front controller 120 transmits key data input by a user via a remote controller or from a front panel of the player, to the system controller 116.
In order to transmit video and audio information from a general DVD player to a display device for display such as a TV receiver or monitor, the DVD player transmits the video and audio signals using predetermined signal lines according to an analog interface. That is, a data transmission channel between the DVD player and the display device for display is installed by a user by directly connecting a plurality of signal lines, that is, a first channel for video and second through sixth channels for audio, from each connector of the DVD player to the display device, so that the video and audio signals provided by the DVD player are transmitted in analog signal form through the signal lines to the display device. For high quality video information transmission, a super video (S-Video) output is separated and transmitted through a specific cable. However, the transmission mode of the super video output is in an analog signal form.
Also, in order to transmit a digital information, DVD players adopt the Sony Philips Digital Interface (SPDIF) in which a video signal is output to its connector as a digital signal and transmitted to the display device through signal lines. However, the SPDIF cannot support complicated functions such as controlling the DVD player via the display device or inspecting the operation status of the DVD player.
The analog interface has the drawback of noise interference during the transmission of a signal. That is, various factors, such as the connection status of a connector, the quality of signal lines or noise generated near the analog interface, can greatly affect the quality of the transmitted video and audio signals, and the fidelity of a transmitted signal is determined by physical characteristics of the signal lines themselves. Also, the analog interface has the following additional problems.
First, a DVD remote controller is required to control a DVD player. Even though a TV set is nothing but a display terminal, it requires a remote controller for controlling the function of the TV set. Thus, if there is the need to connect a plurality of devices, a plurality of remote controllers are required, so that a user becomes inconvenienced.
Second, if an analog interface is used to connect digital devices, the various network functions a digital interface provides cannot be implemented.
If a digital interface such as the IEEE 1394 is adopted, the above problems can be solved. However, the above-mentioned DVD player is manufactured for reproduction in a TV set having an analog input, without careful consideration of a digital TV set. Accordingly, even though the DVD player and a digital TV are connected by the IEEE 1394 interface, it is difficult to reproduce the current standard DVD information using a digital TV. That is, because a digital TV, a receiver for receiving high definition television (HDTV) broadcasting, can process a bit stream having an MPEG-2 Transport Stream (TS) format while the DVD player stores a bit stream having an MPEG-2 Program Stream (PS) format, the format conversion from the MPEG-2 PS format to the MPEG-2 TS format must be done in advance in order to transmit the data from the DVD player through the IEEE 1394 interface to the display device adopting the MPEG-2 TS format.
It is an object of the present invention to provide an apparatus for transmitting digital versatile disc (DVD) information via a network to a display device, in which the display of DVD information can be controlled by the display device according to the control command of a user.
It is another object of the present invention to provide a method for transmitting DVD information via a network to a display device, by which the display of DVD information can be controlled according to the control command of a user.
To achieve the first object, there is an apparatus for transmitting information between devices via a network, comprising: a first device having a transport format converter for receiving user interface data input via a user interface, wherein the user interface is used for commanding and controlling the first device, and for converting information into a transport format for transmission; a second device having a dislay wherein, the display displays the user interface wherein the interface is used for commanding and controlling the first device; and a physical layer for linking the first and second devices.
To achieve the second object, there is provided a method for transmitting information between devices via a network, comprising: connecting a first device to a network, wherein the first device receives user interface data input via a user interface, wherein the user interface is used for commanding and controlling a first device and for converting information to a transport format for transmission; connecting a second device to the network, wherein the second device is used for displaying the user interface for commanding and controlling the first device; receiving the user interface data in the second device; displaying the user interface data in the second device; allowing a user to input a command in response to the user interface displayed in the second device; and transmitting control and command information from the second device to the first device according to the user input, to control access to information provided by the first device.